Experimental Study of the Burning of Pure and Fire Retarded Cellulose

摘要

The burning of charring materials is studied using samples prepared from pure cellulose and the cellulose which has been fire retarded by the addition of Sodium Hydroxide and Sodium Carbonate. The samples which are hemispherically nosed cylinders, are burned in a vertical orientation in a variable oxygen/nitrogen mixture at atmospheric pressure. Ambient oxygen concentration has a stronger effect on the change in burning rate and surface temperature than a proportional change in the retardant concentration. This dominant effect of oxygen concentration is also evident in a significant increase in the amount of retardant needed to cause extinction (both stagnation point and flaming) as the ambient oxygen concentration is increased. At sufficiently high oxygen concentration no extinction is found for the maximum retardant concentration used in this study. A practical consequence of these findings is the need to exercise proper caution in using these retardants in cellulosic products in oxygen rich environments.